Treatment of artificial fabrics and other artificial materials



Patented Jan. 1939 uulreo STATES PATENT um;

TREA'IMENTOF ARTIFICIAL FABRICSAND- OTHER; ARTIFICIAL MATERIALS 1 Robert Wighton Moncrlefl and Frank Brentnall Hill, Spondon, near Derby, England, assignors' to Celanese Corporation of America, a corporation of Delaware No Drawing. Application February 9,1935, Serial No. 5,868. In Great Britain February 21,

11 Claims. (e1. 8 -138) This invention relates to improvements in the treatment of artificial iabrics and other artificial materials, ahd is more particularly directedto the treatment of cellulose ester materials for the purpose of obtaining fabrics or other textile materials of improved physical properties.

'The invention provides a means of improving v the physical properties, particularly the handle, of materials comprising filaments, threads, rib-- bons or the like of organic esters oi. cellulose, which have been stretched and/or twisted under the influence ofsteamor hot water.

The materials treated may comprise yarns or the like of cellulose acetate-or other organic esters of cellulose which have been subjected to treatment with steam or hot water, particularly under conditions of tension which bring about a stretching of the material, so as to produce crepe fabrics, the treatment with the steam or hot water taking place before the application of the crepe twist or during a single stagelcrepe twisting operation or during any of the stages of 'a dior 'multi-stage crepe twisting operation .or between corresponding to British Patent No. 438,599, U. S.

application S. No. 4085 filed January 30, 1935, corresponding to British Patent No. 438,591; and U. S. application S. No.- 4086 filed January 30, 1935, corresponding to British Patent No. 438,588. The materials may moreover comprise yarns or the like of Tcellulose acetate or other cellulose esters which have been stretched with the assistance of steam or hot water as described in U. S. applications S. Nos. 4510 and 4511 both filed February 1, l935,'corresponding to British Patents Nos. 438,584, 438,585, 438,586 and 438,587. The stretching under the influence of steam or hot water may have been applied after the whole of v the crepe twist has been inserted, for example during a bobbin to pirn winding operation or during a bobbin to bobbin winding operation.

We have now found that the physical properties, and in particular the handle, of materials by any of the above methods are substantially improved by non-superficially saponifying the cellulose ester content of the materials to a small extent. The present inventionv contemplates an extremely limited degree of. saponification, for example 'so that the resultantloss in weight of a cellulose acetate materialis of the order of 3 to depth beneath the surface.

6%. It may be even lower or it may be somewhat higher, but preferably the loss in weight does not exceed 10%. Most advantageously the loss in weight is about 4%. With other cellulose esters saponiflcation to an equivalent extent may be care ried out or the degreeof. saponification may be made slightly higher as the molecular weight of the ester radicle increases. The term nonsuperficially is intended to connote that the saponification is not confined to the surface 0! the filaments-or the'like but extends to a substantial While the invention includes aponification with any desired saponitying-agent, i xample caustic soda or caustic potash, we have found that much more valuable results are obtained with saponiiying agents which are somewhat slow in action or which have a substantially lower alkalinity than lias caustic soda. Certain saponii'ying agentswhich have been found particularly suitable 'for saponifying' the materials non-superficially so that a marked improvement in the physical properties, especially handle, is obtained at the expense of little loss in weight, are referred to below.

' A very suitable reagent for the purpose of the invention is sodium silicate. Such a reagent may.

be used, for example, in aqueous solution at a concentration of about 2%, and with this concentration the desired loss in weight may be achieved by means of a treatment for about haltanhour at a temperature of the order oi' IO-85 C. With longer times of treatment and/or higher temperatures, lower concentrations may-be used, while higher concentrations will give the desired loss in weight in a shorter'timeor at a lower temperature. In a similar way other alkali metal salts of weak acids, and especially salts which readilyform colloidal gels, e. g. sodium or potassium silicate, may be used. Again, the strong metallic bases such as caustic soda or caustic potash may be used with advantage inconjunction with gelatine or like acting substances, 1. e. substances, particularly amphoteric substances, of high molecular weight, or organic colloidsrcapable of reducing the alkalinity of the base. Other substances whichmay be employed in this way, e. g. egg albuinen, casein, leucine, potato starch, dextrin, -cellulose and cellobiose, aredescribed inU. S. application S. No. 743,712 filed September 12,

results may be Furthermore, very satisfactory obtained by, means'oif methylamine, ethylamine. .ethylene diamine or similar organic bases (compare U. S. applications S. Nos. 709,335 filed February 1, 1934, and 752,376 flled November 9, 1934) Thus for example one may, by treatment with a 20% solution of methylamine at 20-30 C. or of ethylene diamine at 70-80" C., obtain the desired saponiflcation in the courseipf a few minutes. The saponifying action of the methylamine, ethylene diamineor similar reagent may be accelerated by means of copper or other metals or metal compounds as described in U. S. application S. No. 756,285 filed December 6, 1934.

,The invention also includes the use of caustic soda, caustic potash or the like in presence of alcohols, for instance by the process described in British Patent No. 125,153 and/or in the presence of swelling agents for the cellulose derivative which do not take part in the reaction, as described in U. S. application S. No. 710,349 filed February 8, 1934; i

The saponiflcation treatment may be applied to the materials at any suitable stage after they have been subjected to the treatments described above, for example the stretching in presence of steam or hot water before, during or subsequent to crepe, twisting. Thus, the saponiflcation may be applied before the yarn is formed into fabrics. Preferably, however, the saponiflcation is applied subsequent to fabric formation and subsequent to the development of the crepe figure. The invention does, however, include the saponiflcation of materials which have been stretched in presence of steam or hot water or similar agents, quite apart from the production or crepe fabrics.

The saponiflcation may be carried out in any Most advantageously a bathsuitable manner. treatment is employed, the fabrics or other materials being treated in such a process with a considerable volume of saponifying liquor containing 'thesaponifying agent at the appropriate concentration and temperature. However, the

materials may be saponifled by other suitable obtained by a very limited degree of saponiflcation. The saponiflcation may be such as Just to confer upon the cellulose ester materials an aflinity for cotton colours, but in most cases it will not be suflicient to reduce materially their aflinity for the dispersed insoluble type 01, colour.

Preferably in the case of using organic bases, salts such as sodium silicate or caustic soda, caustic potash or similar strong bases in presence of gelatine or like acting substances, as previously described, the extent of the saponification may be such as not to change substantially the amnity of the materialsfor cotton dyes or for the dispersed insoluble colours. When so treated the materials may retain all the characteristics of cellulose ester materials.

The materials treated in accordance with the invention are considerably improved in handle and particularly they are softer to the touch. The saponiflcation does not impair the crepe figure of the materials, which, as stated in the specifications previously referred to, is very well developed. The process of the invention is particularly important for the treatment of materials which have been very highly twisted, for example those in which the twist is of the order of 70 to 90 turns per inch or more.

What we claim and desire to secure by Letters Patent is:

fluence of water in a fluid phase at an elevated" temperature, comprising subjecting the cellulose ester content of the materials to a deep-seated saponification to an extent insufficient to impart thereto an aflinity for cotton dyes.

2. Process for improving the handle of materails comprising filaments, threads, ribbons and the like of cellulose acetate which have been stretched while being twisted under the influence of water in a fluid phase at an elevated temperature, comprising subjecting the cellulose acetate content of the materials to a deep-seated saponiflcation to an extent insufllcient to impart thereto an affinity for cotton dyes.

3. Process for improving the handle of materials comprising filaments, threads, ribbons and the like of cellulose acetate which have been stretched while being twisted under the influence of water in a fluid phase at an elevated temperature, comprising subjecting the cellulose acetate content of the materials to a deep-seated saponiflcation to an extent insuflicient to impart thereto an aflinity for cotton dyes by treatment in an aqueous bath of low alkalinity.

4. Process for the manufacture of artiflcial materials of improved handle, comprising stretching while twisting filaments, threads, ribbons or the like composed substantially of cellulose acetate, under the influence of water in a fluid phase at an elevated temperature, and subjecting thecellulose acetate content of the materials to a deep-seated saponiflcation to an extent insuificient to impart thereto an afllnity for cotton dyes by treatment in an aqueous saponii'ying bath or low alkalinity.

5. Process for improving the handle of materials comprising filaments, threa'ds, ribbons and the like of organic esters of cellulose which have been stretched under the influence or water in a fluid phase at an elevated temperature, comprising subjecting the cellulose ester content or the material to deep-seated saponiflcation to an extent insuflicient to impart thereto an aflinity for cotton dyes. 4

8. Process for improving the handle of fllaments, threads, ribbons and like materials composed substantially of cellulose acetate, comprising stretching ,the materials under the influence of water in. a fluid phase at an elevated temperature, and subjecting the cellulose. acetate content of the stretched materials to deep-seated saponification without imparting thereto afiinity for cotton dyes to produce loss in weight of 3 to 6% by treatment in an aqueous saponifying bath of low alkalinity. a

7, Process for improving the handle of materails comprising filaments, threads. ribbons and the like of. cellulose acetate which have been stretched while being twisted under the influence or water in a fluid phase at an eleya'ted temperature, comprising subjecting the cellulose acetate content or the materials to deep-seatedsaponiflcation to an extent insufllcient to impart thereto an aflinityjior cotton dyes by treatment in an aqueous bath containing a non-aromatic organic base.

Process for improving the handle of materials comprising fllaments, threads, ribbons and the likev of cellulose acetate which have been stretched while being twisted under the influence or water in a fluid phase at an elevated temperaaqueous bath containing a lower. aliphatic amine.

9. Process'for improving thehandle oi. mate- ,rails comprising filaments, threads, ribbons and the like of cellulose acetate which have been stretched while being twisted under, the influence oilwater in-a fluid phase at an elevated temperature, comprising subjecting the cellulose acetate content of the materials to deep-seated saponification without imparting thereto an afiinity for cotton dyes to produce a loss of weight of 3 to 6% by treatment in an aqueous bath containing mono-methylamine. v

10. Process for improving the handle of materials comprising filaments, threads,- ribbons and the like of cellulose acetate which have been stretched while being twisted'under the influence of water in a fluid phase at an elevated temperature, comprising subjecting the cellulose acetate content of the materials to deep-seated saponificaticn without imparting thereto an afiinity for cotton dyesto produce a lossof weight of 3 to 6% by treatment in an aqueous bath containing ethylene diamine.

11. Process for improving the handle of materials comprising filaments, threads, ribbons and the like of cellulose acetate which have been crepe twisted under the influence of water in a fluid phase at an elevated temperature, comprising. subjecting the cellulose acetate content of the materials to deep-seated saponification to an extent insufficient to impart thereto an afiinity for cotton dyes by treatment in an aqueous saponify ing bath of low alkalinity. .t

ROBERT WIGHTONS MONCRIEFF. FRANK BRENTNALL 

